This invention relates to signs or displays for displaying prices of items in stores and restaurants, for example. In particular, the invention is an improvement in the kind of display device that has characters or numerals for composing a price imprinted on adjacent precoiled and self-recoiling plastic tapes where the tapes pass windows to display the numerals and to allow access with a finger so the tapes can be translated to positions where all of the numerals in a row compose the price.
A display device using precoiled tapes is illustrated in U.S. Pat. No. 3,939,584, dated Feb. 24, 1976, which is assigned to the assignee of this application. The improvement of the present invention over the patented device is to provide a simple means for performing the dual functions of pressing any wrinkles or bulges out of the tapes in the window areas and also to lock the tapes more positively in the window areas and thereby prevent inadvertent translation or slipping.
In the display device referred to above, the plastic tapes on which the numerals are imprinted have internal stress which causes the free ends of the tapes to become self-coiling or self-winding when the tape ends are unrestrained. The tapes are installed in a holder having adjacent windows for exposing the sequences of numerals which are printed on them and which are used to compose a price. There are flanges or tracks at the side edges of each window for guiding the tapes past the windows. The holders have platens for backup walls, respectively, extending across the windows behind the tapes. The platens, which are molded integrally with the holders, are curved and intended to take up slack and restrain the tape against wrinkling or bulging. Another purpose of the platens is to permit a user to apply fingertip pressure on the tapes followed by a frictional translating force in order to index the sequence of numerals past the window.
Because of the prestressed numeral bearing tapes having a tendency to coil at both ends, the tapes were not always pulled tightly against the platens. This adversely affected the appearance of the row of numerals composing the price. A tape bulging problem also occurred on some occasions. This was because the tapes were bent sharply rearwardly toward the place where the coils are formed. If no change was made in the tape position for an extended period of time, the bends would take on a tentatively permanent set, especially if the tapes were exposed to heat such as from the sun. Then, when a tape was translated by the amount of one numeral to set up a new price, a bulge or wrinkle would often occur in the window where the tape had taken on the permanent set.